ISL6141IBZA-T [INTERSIL]
Negative Voltage Hot Plug Controller; 负电压热插拔控制器型号: | ISL6141IBZA-T |
厂家: | Intersil |
描述: | Negative Voltage Hot Plug Controller |
文件: | 总19页 (文件大小:426K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
ISL6141, ISL6151
®
Data Sheet
July 2004
FN9079.1
Negative Voltage Hot Plug Controller
Features
The ISL6141 is an 8-pin, negative voltage hot plug controller
that allows a board to be safely inserted and removed from a
live backplane. Inrush current is limited to a programmable
value by controlling the gate voltage of an external N-
channel pass transistor. The pass transistor is turned off if
the input voltage is less than the Under-Voltage threshold, or
greater than the Over-Voltage threshold. The IntelliTripTM
electronic circuit breaker and programmable current limit
features protect the system against short circuits. When the
Over-Current threshold is exceeded, the output current is
limited for 600µs before the circuit breaker shuts down the
FET. If the fault disappears before the 600µs time-out,
normal operation resumes. In addition, the IntelliTripTM
electronic circuit breaker has a fast Hard Fault shutdown with
a threshold set at 4 times the current limit value. When
activated, the GATE is immediately turned off and then
slowly turned back on for a single retry (soft-start). The
active low PWRGD signal can be used to directly enable a
power module (with a low enable input). The ISL6151 is the
same device but has an active high PWRGD output.
• Operates from -20V to -80V (-100V Absolute Max Rating)
• Programmable Inrush Current
• Programmable Over-Voltage Protection
• Programmable Under-Voltage Protection
- 135mV of hysteresis
- Equals ~4.6V of hysteresis at the power supply
• UVLO (Under-Voltage Lock-Out) ~ 16.5V
• Programmable Current Limit with 600µs time-out
• IntelliTripTM electronic circuit breaker distinguishes
between Over-Current and Hard Fault conditions
- Fast shutdown for Hard Faults with a single retry (fault
current > 4X current limit value).
• Pin Compatible with ISL6140/50.
• Power Good Control Output
- Monitors both the DRAIN (voltage drop across the FET)
and the GATE voltage; once both are OK, the Power
Good output is latched in the active state.
- PWRGD active high: ISL6151 (H version)
- PWRGD active low: ISL6141 (L version)
Typical Application (RL, CL are the Load)
GND
GND
• Pb-free available
R4
Applications
V
DD
UV
OV
• VoIP (Voice over Internet Protocol) Servers
• Telecom systems at -48V
PWRGD
R5
R6
ISL6141
SENSE GATE
C1
V
DRAIN
C2
EE
• Negative Power Supply Control
• +24V Wireless Base Station Power
(LOAD)
CL
R3
R2
RL
Related Literature
-48V IN
• ISL6140/41 EVAL1 Board Set, Document # AN9967
• ISL6142/52 EVAL1 Board Set, Document # AN1000
• ISL6140/50 Hot Plug Controller, Document # FN9039
• ISL6116 Hot Plug Controller, Document # FN4778
NOTE: See www.intersil.com/hotplug for more information.
R1
Q1
-48V OUT
R1 = 0.02Ω (1%)
R2 = 10Ω (5%)
C1 = 150nF (25V)
C2 = 3.3nF (100V)
R3 = 18kΩ (5%)
R4 = 549kΩ (1%)
R5 = 6.49kΩ (1%)
R6 = 10kΩ (1%)
Q1 = IRF530 (100V, 17A, 0.11Ω)
CL = 100µF (100V)
Pinout
RL = equivalent load
ISL6141 OR ISL6151 (8 LEAD SOIC)
8
7
6
5
1
2
3
4
V
PWRGD/PWRGD
DD
TOP VIEW
OV
DRAIN
GATE
UV
V
SENSE
EE
ISL6141 has active low (L version) PWRGD output pin
ISL6151 has active high (H version) PWRGD output pin
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 321-724-7143 | Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright © Intersil Americas Inc. 2002, 2004. All Rights Reserved
1
Intellitrip™ is a trademark of Intersil Americas Inc.
ISL6141, ISL6151
Ordering Information (Continued)
Ordering Information
PKG.
DWG. #
PKG.
DWG. #
o
o
PART NO.
TEMP. RANGE ( C) PACKAGE
-40 to 85
PART NO.
ISL6141CB
TEMP. RANGE ( C) PACKAGE
ISL6151IBZA
(See Note)
8 Lead SOIC M8.15
(Pb-free)
0 to 70
0 to 70
8 Lead SOIC M8.15
8 Lead SOIC M8.15
ISL6141CBZA
(See Note)
*Add “-T” suffix to part number for tape and reel packaging.
(Pb-free)
ISL6151CB
0 to 70
0 to 70
8 Lead SOIC M8.15
NOTE: Intersil Pb-free products employ special Pb-free material
sets; molding compounds/die attach materials and 100% matte tin
plate termination finish, which is compatible with both SnPb and
Pb-free soldering operations. Intersil Pb-free products are MSL
classified at Pb-free peak reflow temperatures that meet or exceed
the Pb-free requirements of IPC/JEDEC J Std-020B.
ISL6151CBZA
(See Note)
8 Lead SOIC M8.15
(Pb-free)
ISL6141IB
-40 to 85
-40 to 85
8 Lead SOIC M8.15
ISL6141IBZA
(See Note)
8 Lead SOIC M8.15
(Pb-free)
ISL6151IB
-40 to 85
8 Lead SOIC M8.15
GND
GND
V
DD
-
UVLO
1.265V
R4
R5
+
+
REGULATOR,
REFERENCES
-
V
V
EE
EE
UV
OV
-
13V
UV
OV
1.255V
+
+
-
V
EE
+
-
1.255V
LOGIC
+
-
TIMING
V
EE
GATE DRIVE
-
R6
HARD
FAULT
210mV
+
+
-
V
EE
GATE
-
11.1V
+
+
-
CURRENT
LIMIT
-
PWRGD
50mV
OUTPUT
+
REGULATOR
(ISL6141)
V
EE
DRIVE
-
+
PWRGD
(ISL6151)
-
LATCH
LOGIC
1.3V
+
V
+
EE
-
V
EE
600µs
TIMER
PWRGD
PWRGD
GATE
GATE
R3
DRAIN
SENSE
V
EE
LOAD
CL
C2
R2
RL
C1
-48V OUT
-48V IN
R1
Q1
FIGURE 1. BLOCK DIAGRAM
2
ISL6141, ISL6151
external FET. The built in 25mV hysteresis will keep the
GATE off until the OV pin drops below 1.230V, which is the
nominal high to low threshold. A typical application will use
Pin Descriptions
PWRGD (ISL6141; L Version) Pin 1
This digital output is an open-drain pull-down device. During
start-up the DRAIN and GATE voltages are monitored with
two separate comparators. The first comparator looks at the
an external resistor divider from V
level as desired. A three-resistor divider can be used to set
both OV and UV trip points.
to V to set the OV
DD
EE
DRAIN pin voltage compared to the internal V
(V
PG
the external FET and sense resistor. When the DRAIN to V
voltage drop is less than 1.3V, the first of two conditions
required for the power to be considered good are met. In
addition, the GATE voltage monitored by the second
comparator must be within approximately 2.5V of its normal
operating voltage (13.6V). When both criteria are met the
PWRGD output will transition from high to low, enabling a
power module in some applications. The output is latched in
the low state until any of the signals that shut off the GATE
occur (Over-Voltage, Under-Voltage, Under-Voltage Lock-Out,
Over-Current Time-Out, or powering down). Any of these
conditions will re-set the latch and the PWRGD output will
transition from low to high indicating power is no longer good.
In this case the output pull-down device shuts off, and the pin
becomes high impedance. Typically an external pull-up of
some kind is used to pull the pin high (many brick regulators
have a pull-up function built in).
reference
is nominal 1.3V); this measures the voltage drop across
PG
UV (Under-Voltage) Pin 3 - This analog input compares the
voltage on the pin to an internal comparator with a built in
hysteresis of 135mV. When the UV input goes below the
nominal reference (high to low transition) voltage of 1.120V,
the GATE pin is immediately pulled low to shut off the
external FET. Since the comparator has a built in 135mV
hysteresis the GATE will remain off until the UV pin rises
above a 1.255V low to high threshold. A typical application
EE
will use an external resistor divider from V
to V to set
DD
EE
the UV level as desired. A three-resistor divider can be used
to set both OV and UV trip points.
The UV pin is also used to reset the Over-Current latch. The
pin must be cycled below 1.120V (nominal) and then above
1.255V (nominal) to clear the latch and initiate a normal
power-up sequence.
V
Pin 4 - This is the most negative supply voltage, such
EE
as in a -48V system. Most of the other signals are referenced
relative to this pin, even though it may be far away from what
is considered a GND reference.
PWRGD (ISL6151; H Version) Pin 1 - This digital
output is used to provide an active high signal to enable an
external module. The Power Good comparators are the
same as described above, but the active state of the output
is reversed (reference Figure 33).
SENSE Pin 5 - This analog input monitors the voltage drop
across the external sense resistor (between SENSE and
V
) to determine if the current exceeds the programmed
EE
Over-Current trip point, equal to 50mV / Rsense. If the load
current exceeds the Over-Current threshold, the circuit will
regulate the current to maintain the nominal voltage drop
(50mV) across the sensing resistor R1 (Rsense). If current is
limited for more than 600µs, the Over-Current shutdown
(also called electronic circuit breaker) will quickly turn off the
FET and latch the GATE pin off.
If the latch is reset (GATE turns off), the internal DMOS
device (Q3) is turned off, and Q2 (NPN) turns on to clamp
the output one diode drop above the DRAIN voltage to
produce a logic low.
Once the latch is set (both DRAIN and GATE are normal), the
DMOS device (Q3) turns on and sinks current to V through
EE
a 6.2KΩ resistor. The base of Q2 is clamped to V to turn it
A Hard Fault comparator is employed to detect and respond
quickly to severe short circuits. The threshold of this
EE
off. If the external pull-up current is high enough (>1mA, for
example), the voltage drop across the resistor will be large
enough to produce a logic high output (in this example, 1mA *
6.2kΩ = 6.2V) and enable the external module.
comparator is set approximately four times higher (210mV)
than the Over-Current trip point. When its threshold is
exceeded the GATE is immediately (10µs typical) shut off,
the timer is reset, and a single retry (soft start) is attempted
before latching the GATE off (assuming the fault remains).
During the retry, if the fault disappears prior to the Over-
Current Time-Out period (600µs) the FET will remain on as
normal. If the GATE is latched off, the user must either toggle
the UV pin below then above its threshold, or reduce the
Note that for all H versions, although this is a digital pin
functionally, the logic high level is determined by the external
pull-up device, and the power supply to which it is
connected; the IC will not clamp it below the V
voltage.
DD
Therefore, if the external device does not have its own
clamp, or if it would be damaged by a high voltage, an
external clamp might be necessary.
supply voltage below the V
above it. This will clear the latch and initiate a normal power-
up sequence.
UVLO trip point and then
DD
OV (Over-Voltage) Pin 2 - This analog input compares the
voltage on the pin to an internal voltage reference of 1.255V
(nominal). When the input goes above the reference (low to
high transition) an Over-Voltage condition is detected and
the GATE pin is immediately pulled low to shut off the
3
ISL6141, ISL6151
GATE Pin 6 - This analog output drives the gate of the
external FET used as a pass transistor. The GATE pin is high
(FET is on) when the following conditions are met:
• UVLO is above its trip point (~16.5V)
• Voltage on the UV pin is above its trip point (1.255V)
• Voltage on the OV pin is below its trip point (1.255V)
• No Over-Current conditions are present.
If any of the 4 conditions are violated, the GATE pin will be
pulled low to shut off or regulate current through the FET.
The GATE is latched off only when the 600µs Over-Current
Time-Out period is exceeded.
The GATE is driven high by a weak (-50µA nominal) pull-up
current source, in order to slowly turn on the FET. It is driven
low by a 70mA nominal pull-down device for three of the
above shut-off conditions. A larger (350mA nominal) pull-
down current shuts off the FET very quickly in the event of a
hard fault where the sense pin voltage exceeds
approximately 210mV.
DRAIN Pin 7 - This is the analog input to one of two
comparators that control the PWRGD (ISL6141) or PWRGD
(ISL6151) outputs. It compares the voltage of the external
FET DRAIN to a 1.3V internal reference (V ). The DRAIN
PG
voltage is criticized only until the PWRGD or PWRGD
outputs are latched into their active low or high states. The
latch is reset when any of the conditions that turn off the
GATE occur (UVLO, OV, UV, OC Time-Out). Note that the
comparator does NOT itself turn off the GATE.
V
Pin 8 - This is the most positive power supply pin. It can
DD
range from the Under-Voltage Lock-Out threshold (16.5V) to
+80V (Relative to V ).
EE
4
ISL6141, ISL6151
.
Absolute Maximum Ratings
Thermal Information
o
Supply Voltage (V
to V ). . . . . . . . . . . . . . . . . . . . -0.3V to 100V
EE
Thermal Resistance (Typical, Note 1)
θ
( C/W)
DD
JA
DRAIN, PWRGD, PWRGD Voltage . . . . . . . . . . . . . . .-0.3V to 100V
UV, OV Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 60V
SENSE, GATE Voltage . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 20V
ESD Rating
8 Lead SOIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maximum Junction Temperature (Plastic Package) . . . . . . . .150 C
Maximum Storage Temperature Range. . . . . . . . . . -65 C to 150 C
Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . .300 C
90
o
o
o
o
Human Body Model (Per MIL-STD-883 Method 3015.7) . . .2000V
Operating Conditions
o
o
Temperature Range (Industrial) . . . . . . . . . . . . . . . . . -40 C to 85 C
Temperature Range (Commercial). . . . . . . . . . . . . . . . . 0 C to 70 C
Supply Voltage Range (Typical). . . . . . . . . . . . . . . . . . . 36V to 72V
o
o
CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the
device at these or any other conditions above those indicated in the operational sections of this specification is not implied.
NOTES:
1. θ is measured with the component mounted on a high effective thermal conductivity test board in free air. See Tech Brief TB379 for details.
JA
2. PWRGD is referenced to DRAIN; V = 0V.
-V
PWRGD DRAIN
Electrical Specifications
V
= +48V, V = +0V Unless Otherwise Specified. All tests are over the full temperature range; either
EE
DD
Commercial (0 C to 70 C) or Industrial (-40 C to 85 C). Typical specs are at 25 C.
o
o
o
o
o
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
Units
DC PARAMETERS
V
PIN
DD
Supply Operating Range
Supply Current
V
20
-
80
V
DD
I
UV = 3V; OV = V ; SENSE = V ; V
=
2.4
4.5
mA
DD
EE
EE DD
80V
UVLO High
V
V
V
Low to High transition
High to Low transition
15
13
16.7
14.8
1.9
19
17
V
V
V
UVLOH
DD
DD
UVLO Low
V
UVLOL
UVLO hysteresis
GATE PIN
GATE Pin Pull-Up Current
GATE Pin Pull-Down Current
GATE Pin Pull-Down Current
GATE Pin Pull-Down Current
I
GATE Drive on, V
V
GATE = EE
-30
-50
70
-60
15
µA
mA
mA
mA
V
PU
I
GATE Drive off, UV or OV false
PD1
PD2
PD3
I
I
GATE Drive off, Over-Current Time-Out
70
GATE Drive off; Hard Fault (Vsense > 210mV)
350
13.6
2.5
External GATE Drive (V
= 20V, 80V)
∆ V
(V
V
, 20V <=V
DD
<=80V
12
40
DD
GATE
GATE - EE)
GATE High Threshold (PWRGD/PWRGD
active)
V
∆V - V
V
GH
GATE
GATE
SENSE PIN
Current Limit Trip Voltage
Hard Fault Trip Voltage
SENSE Pin Current
UV PIN
V
V
V
V
= (V
- V
)
50
60
mV
mV
µA
CL
CL
SENSE
EE
V
= (V
- V
)
210
-1.3
HFT
HFTV
SENSE
= 50mV
EE
I
-4.0
SENSE
SENSE
UV Pin High Threshold Voltage
UV Pin Low Threshold Voltage
UV Pin Hysteresis
V
UV Low to High Transition
UV High to Low Transition
1.240
1.105
1.255
1.120
135
1.270
1.145
V
V
UVH
V
UVL
V
mV
UVHY
5
ISL6141, ISL6151
Electrical Specifications
V
= +48V, V = +0V Unless Otherwise Specified. All tests are over the full temperature range; either
EE
DD
o
o
o
o
o
Commercial (0 C to 70 C) or Industrial (-40 C to 85 C). Typical specs are at 25 C. (Continued)
PARAMETER
UV Pin Input Current
OV pin
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
Units
I
V
= V
EE
-0.05
-0.5
µA
INUV
UV
OV Pin High Threshold Voltage
OV Pin Low Threshold Voltage
OV Pin Hysteresis
V
OV Low to High Transition
OV High to Low Transition
1.235
1.215
1.255
1.230
25
1.275
1.255
V
V
OVH
V
OVL
V
mV
µA
OVHY
INOV
OV Pin Input Current
DRAIN Pin
I
V
= V
-0.05
-0.5
OV
EE
Power Good Threshold (PWRGD/PWRGD
active)
V
V
V
- V
0.80
1.30
38
2.00
60
V
PG
DRAIN
DRAIN
EE
DRAIN Input Bias Current
I
= 48V
µA
DRAIN
ISL6141 (PWRGD Pin: L Version)
PWRGD Output Low Voltage
V
V
(V
(V
- V
- V
< V
< V
I
PG; OUT
= 1mA
= 5mA
-
-
-
0.30
1.50
0.05
1.0
3.0
10
V
V
OL1
OL5
DRAIN
DRAIN
DRAIN
EE)
EE)
I
PG; OUT
Output Leakage
I
V
= 48V, V
= 80V
PWRGD
µA
OH
ISL6151 (PWRGD Pin: H Version)
PWRGD Output Low Voltage (PWRGD-DRAIN)
PWRGD Output Impedance
AC Timing
V
V
= 5V, I
= 1mA
PG
-
0.85
6.2
1.0
9.0
V
OL
DRAIN
OUT
< V
R
(V
- V
EE)
3.5
kΩ
OUT
DRAIN
OV High to GATE Low
t
t
Figures 2A, 3A
Figures 2A, 3A
Figures 2A, 3B
Figures 2A, 3B
Figures 2A, 6
Figures 2B, 8
0.6
1.0
0.6
1.0
1.3
4.5
3.0
12.0
3.0
12.0
3
µs
µs
µs
µs
µs
µs
µs
PHLOV
PLHOV
OV Low to GATE High
UV Low to GATE Low
t
t
0.90
5.0
PHLUV
PLHUV
UV High to GATE High
SENSE High to GATE Low
Current Limit to GATE Low (O.C. Time-out)
t
0.35
600
10
PHLSENSE
t
PHLCB
Hard Fault to GATE Low (200mV comparator)
Typical GATE shutdown based on application
ckt. Guaranteed by design.
t
Figures 7, 23, 27 (zero Ω short to V
)
DD
PHLHF
ISL6141 (L Version)
DRAIN Low to PWRGD Low
GATE High to PWRGD Low
ISL6151 (H Version)
t
Figures 2A, 4A (note 2)
Figures 2A, 5A (note 2)
3.0
1.0
5.0
3.0
µs
µs
PHLDL
t
PHLGH
DRAIN Low to (PWRGD-DRAIN) High
GATE High to (PWRGD-DRAIN) High
t
Figures 2A, 4B (note 2)
Figures 2A, 5B (note 2)
3.0
0.4
5.0
3.0
µs
µs
PLHDL
t
PLHGH
6
ISL6141, ISL6151
Test Circuit and Timing Diagrams
5V
R = 5K
5V
+
48V
-
R = 5K
+
48V
-
V
PWRGD
OV
DD
8
7
6
5
1
2
3
4
V
V
PWRGD
OV
DD
DRAIN
8
7
6
5
1
2
3
4
V
V
DRAIN
GATE
DRAIN
OV
ISL6141
ISL6151
DRAIN
GATE
ISL6141
ISL6151
9.0KΩ
UV
V
OV
UV
V
EE
SENSE
V
EE
SENSE
V
0.9KΩ
UV
V
UV
0.1KΩ
V
SENSE
.
FIGURE 2A. TYPICAL TEST CIRCUIT
FIGURE 2B. TEST CIRCUIT FOR 600µs TIME-OUT
OV Pin
1.255V
2V
2V
1.120V
1.255V
1.230V
UV Pin
GATE
0V
0V
t
t
PLHUV
t
PHLUV
t
PHLOV
PLHOV
13.6V
13.6V
1V
1V
1V
1V
GATE
0V
0V
FIGURE 3B. UV TO GATE TIMING
FIGURE 3A. OV TO GATE TIMING
FIGURE 3. OV AND UV TO GATE TIMING
DRAIN
DRAIN
1.3V
1.3V
V
PG
V
PG
V
EE
V
t
EE
t
PHLDL
PHLDL
PWRGD
1.0V
1.0V
PWRGD
FIGURE 4A. DRAIN TO PWRGD TIMING (ISL6141)
FIGURE 4B. DRAIN TO PWRGD TIMING (ISL6151)
FIGURE 4. DRAIN TO PWRGD/PWRGD TIMING
∆V
- V
= 0V
GATE
GATE
∆V
- V = 0V
GATE
GATE
V
2.5V
GH
V
2.5V
GH
GATE
t
PLHGH
GATE
t
PHLGH
PWRGD
1.0V
= 0V
PWRGD
1.0V
V
- V
DRAIN
PWRGD
FIGURE 5A. GATE TO PWRGD (ISL6141)
FIGURE 5. GATE TO PWRGD/PWRGD TIMING
FIGURE 5B. GATE TO PWRGD (ISL6151)
7
ISL6141, ISL6151
Test Circuit and Timing Diagrams (Continued)
50mV
210mV
SENSE
GATE
SENSE
0V
13.6V
GATE
t
PHLSENSE
t
PHLHF
V
~4V (depends on FET threshold)
EE
FIGURE 6. SENSE TO GATE TIMING
FIGURE 7. SENSE TO GATE (Hard Fault) TIMING
UV
t
PHLCB
GATE
1.0V
1.0V
FIGURE 8. CURRENT LIMIT TO GATE TIMING
Typical Performance Curves
4.5
4
3.5
3
2.5
2
1.5
1
2.3
2.25
2.2
2.15
2.1
2.05
2
0.5
0
1.95
10 20 30 40 50 60 70 80 90 100
Supply Voltage (VDD)
-40
-20
0
20
40
60
80
100
Temperature (C)
o
FIGURE 9. SUPPLY CURRENT VS. SUPPLY VOLTAGE (25 C)
FIGURE 10. SUPPLY CURRENT VS. TEMPERATURE, V = 48V
DD
8
ISL6141, ISL6151
Typical Performance Curves (Continued)
16
14
12
10
8
2.45
2.4
2.35
2.3
2.25
2.2
6
4
2
0
2.15
2.1
10
20
30
40
50
60
70
80 100
-40
-20
0
20
40
60
80
100
Supply Voltage (VDD)
Temperature (C)
o
FIGURE 11. SUPPLY CURRENT VS TEMPERATURE, V
= 80V
FIGURE 12. GATE VOLTAGE VS SUPPLY VOLTAGE (25 C)
DD
14
13.9
13.8
13.7
13.6
13.5
13.4
14
13.9
13.8
13.7
13.6
13.5
13.4
13.3
-40
-20
0
20
40
60
80
100
-40
-20
0
20
40
60
80
100
Temperature (C)
Temperature (C)
FIGURE 13. GATE VOLTAGE VS TEMPERATURE, V
= 48V
FIGURE 14. GATE VOLTAGE VS TEMPERATURE, V
= 80V
DD
DD
14
13.9
13.8
13.7
13.6
13.5
13.4
50
49
48
47
46
45
44
43
42
41
-40
-20
0
20
40
60
80
100
-40
-20
0
20
40
60
80
100
Temperature (C)
Temperature (C)
FIGURE 15. GATE VOLTAGE VS TEMPERATURE, V
= 20V
FIGURE 16. GATE PULL-UP CURRENT VS TEMPERATURE
DD
9
ISL6141, ISL6151
Typical Performance Curves (Continued)
450
400
350
300
250
200
150
100
50
90
80
70
60
50
40
30
20
10
0
0
-40
-20
0
20
40
60
80
100
-40
-20
0
20
40
60
80
100
Temperature (C)
Temperature (C)
FIGURE 17. GATE PULL-DOWN CURRENT
(UV/OV/TIME-OUT) VS TEMPERATURE
FIGURE 18. HARD FAULT GATE PULL-DOWN CURRENT
(200mV COMPARATOR) VS TEMPERATURE
54
52
50
48
46
44
42
40
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
5mA
1mA
-40
-20
0
20
40
60
80
100
-40
-20
0
20
40
60
80
100
Temperature (C)
Temperature (C)
FIGURE 19. OVER-CURRENT TRIP VOLTAGE VS
TEMPERATURE
FIGURE 20. PWRGD (ISL6141) V
VS TEMPERATURE
OL
2
6.8
6.7
6.6
6.5
6.4
6.3
6.2
6.1
1.5
1
0.5
0
-40
-20
0
20
40
60
80
100
-40
-20
0
20
40
60
80
100
Temperature (C)
Temperature (C)
FIGURE 21. PWRGD (ISL6151) IMPEDANCE VS
TEMPERATURE
FIGURE 22. DRAIN to PWRGD / PWRGD TRIP VOLTAGE (V
VS TEMPERATURE
)
PG
10
ISL6141, ISL6151
Applications Information
GND
R4
V
DD
UV
OV
R5
R6
ISL6141
SENSE GATE
C1
PWRGD
DRAIN
V
EE
(LOAD)
CL
R3
C2
R2
RL
-48V IN
R1
Q1
-48V OUT
FIGURE 23. TYPICAL APPLICATION WITH MINIMUM COMPONENTS
input power supply is divided down such that when the
Typical Values for a representative system; which
assumes:
voltage on the OV pin is below its threshold and the UV pin is
above its threshold their comparators will be in the proper
state signaling the supply is within its desired range, allowing
the GATE to turn on. The equations below define the
comparator thresholds for an increasing (in magnitude)
supply voltage.
• 43V to 71V supply range; 48 nominal; UV = 43V;
OV = 71V
• 1Amp of typical current draw; 2.5 Amp Over-Current
• 100µF of load capacitance (CL); equivalent RL of 48Ω
(R = V/I = 48V/1A)
〈 R + R + R 〉
4
5
6
(EQ. 1)
----------------------------------------
V
=
× 1.255
UV
(R + R )
R1: 0.02Ω (1%)
5
6
R2: 10Ω (5%)
〈 R + R + R 〉
4
5
6
(EQ. 2)
----------------------------------------
V
=
× 1.255
OV
(R )
6
R3: 18kΩ (5%)
The values of R4 = 549K, R5 = 6.49K, and R6 = 10K shown
in figure 23 set the Under-Voltage turn-on threshold to 43V,
and the Over-Voltage turn off threshold to 71V. The Under-
Voltage (UV) comparator has a hysteresis of 135mV (4.6V of
hysteresis on the supply) which correlates to a 38.4V turn off
voltage. The Over-Voltage comparator has a 25mV
hysteresis which translates to a turn on voltage (supply
decreasing) of approximately 69.6V.
R4: 549kΩ (1%)
R5: 6.49kΩ (1%)
R6: 10kΩ (1%)
C1: 150nF (25V)
C2: 3.3nF (100V)
Q1: IRF530 (100V, 17A, 0.11Ω)
Q1 - is the FET that connects the input supply voltage to the
output load, when properly enabled. It needs to be selected
based on several criteria:
Quick Guide to Choosing Component
Values
• Maximum voltage expected on the input supply (including
transients) as well as transients on the output side.
(See fig 23 for reference)
This section will describe the minimum components needed
for a typical application, and will show how to select
component values. (Note that “typical” values may only be
good for this application; the user may have to select
alternate component values to optimize performance for
other applications). Each block will then have more detailed
explanation of how the device works, and alternatives.
• Maximum current and power dissipation expected during
normal operation, usually at a level just below the current
limit threshold.
• Power dissipation and/or safe-operating-area
considerations during current limiting and single retry
events.
• Other considerations include the GATE voltage threshold
R4, R5, R6 - together set the Under-Voltage (UV) and Over-
Voltage (OV) trip points. When the power supply ramps up
and down, these trip points (and their hysteresis) will
determine when the GATE is allowed to turn on and off (UV
and OV do not control the PWRGD / PWRGD output). The
which affects the r
(which in turn, affects the
DS(ON)
voltage drop across the FET during normal operation),
and the maximum GATE voltage allowed (the ICs GATE
output is clamped to ~14V).
11
ISL6141, ISL6151
R1 - Is the Over-Current sense resistor. If the input current is
case of a regulator, there may be capacitors on the output of
that circuit as well; these need to be added into the
capacitance calculation during inrush (unless the regulator is
delayed from operation by the PWRGD signal).
high enough, such that the voltage drop across R1 exceeds
the SENSE comparator trip point (50mV nominal), the GATE
pin will be pulled lower (to ~4V) and current will be regulated
to 50mV/Rsense for approximately 600µs. The Over-Current
threshold is defined in Equation 3 below. If the 600µs time-
out period is exceeded the Over-Current latch will be set and
the FET will be turned off to protect the load from excessive
current. A typical value for R1 is 0.02Ω, which sets an Over-
RL - is the equivalent resistive value of the load and
determines the normal operation current delivered through
the FET. It also affects some dynamic conditions (such as
the discharge time of the load capacitors during a power-
down). A typical value might be 48Ω (I = V/R = 48/48 = 1A).
Current trip point of; I
= V/R = 0.05/0.02 = 2.5 Amps. To
OC
select the appropriate value for R1, the user must first
determine at what level of current it should trip, take into
account worst case variations for the trip point (50mV
±10mV = ±20%), and the tolerances of the resistor (typically
1% or 5%). Note that the Over-Current threshold should be
set above the inrush current level plus the expected load
current to avoid activating the current limit and time-out
circuitry during start-up. If the power good output is used to
enable an external module, the desired inrush current only
needs to be considered. One rule of thumb is to set the
Over-Current threshold 2-3 times higher than the normal
operating current.
R2, C1, R3, C2 - are related to the GATE driver, as it
controls the inrush current.
R2 prevents high frequency oscillations; 10Ω is a typical
value. R2 = 10Ω.
R3 and C2 act as a feedback network to control the inrush
current as shown in equation 4 below, where CL is the load
capacitance (including module input capacitance), and I is
PU
the GATE pin charging current, nominally 50µA.
C
L
C
2
------
(EQ. 4)
I
= I
×
PU
inrush
50mv
I
= -------------------
OC
(EQ. 3)
R
sense
Begin by choosing a value of acceptable inrush current for
the system, and then solve for C2.
Physical layout of R1 SENSE resistor is critical to avoid
the possibility of false over current events. Since it is in the
main input-to-output path, the traces should be wide enough
to support both the normal current, and up to the over-
current trip point. Ideally trace routing between the R1
C1 and R3 prevent Q1 from turning on momentarily when
power is first applied. Without them, C2 would pull the gate
of Q1 up to a voltage roughly equal to V *C2/Cgs(Q1)
EE
(where Cgs is the FET gate-source capacitance) before the
ISL6141/2 could power up and actively pull the gate low.
Place C1 in parallel with the gate capacitance of Q1; isolate
them from C2 by R3.
resistor and the ISL6141/51 (pin 4 (V ) and pin 5 (SENSE)
EE
is direct and as short as possible with zero current in the
sense lines. (See Figure 24).
C1= [(Vinmax - Vth)/Vth] * (C2+Cgd) - where Vth is the
FET’s minimum gate threshold, Vinmax is the maximum
operating input voltage, and Cgd is the FET gate-drain
capacitance.
CORRECT
INCORRECT
R3 - its value is not critical, a typical value of 18kΩ is
recommended but values down to 1KΩ can be used. Lower
values of R3 will add delay to the gate turn-on for hot
insertion and the single retry event following a hard fault.
To SENSE
and V
EE
Note that although this IC was designed for -48V systems, it
can also be used as a low-side switch for positive 48V
systems; the operation and components are usually similar.
One possible difference is the kind of level shifting that may
be needed to interface logic signals to the UV input (to reset
the latch) or PWRGD output. For example, many of the IC
functions are referenced to the IC substrate, connected to
CURRENT
SENSE RESISTOR
FIGURE 24. SENSE RESISTOR LAYOUT GUIDELINES
CL - is the sum of all load capacitances, including the load’s
input capacitance itself. Its value is usually determined by
the needs of the load circuitry, and not the hot plug (although
there can be interaction). For example, if the load is a
regulator, then the capacitance may be chosen based on the
input requirements of that circuit (holding regulation under
current spikes or loading, filtering noise, etc.) The value
chosen will affect the peak inrush current. Note that in the
the V pin. But this pin may be considered -48V or GND,
depending upon the polarity of the system. And input or
output logic (running at 5V or 3.3V or even lower) might be
EE
externally referenced to either V
of GND.
or V of the IC, instead
EE
DD
12
ISL6141, ISL6151
Inrush Current Control
Electronic Circuit Breaker/Current Limit
The primary function of the ISL6141 hot plug controller is to
control the inrush current. When a board is plugged into a
live backplane, the input capacitors of the board’s power
supply circuit can produce large current transients as they
charge up. This can cause glitches on the system power
supply (which can affect other boards!), as well as possibly
cause some permanent damage to the power supply.
The ISL6141/51 features programmable current limiting with a
fixed 600µs time-out period to protect against excessive
supply or fault currents. The IntelliTripTM electronic circuit
breaker is capable of detecting both hard faults, and less
severe Over-Current conditions.
The Over-Current trip point is determined by R1 (Eq. #3) also
referred to as Rsense. When the voltage across this resistor
exceeds 50mV, the current limit regulator will turn on, and the
GATE will be pulled lower (to ~4V) to regulate current through
the FET at 50mV/Rsense. If the fault persists and current
limiting exceeds the 600µs time-out period, the FET will be
The key to allowing boards to be inserted into a live
backplane is to turn on the power to the board in a controlled
manner, usually by limiting the current allowed to flow
through a FET switch, until the input capacitors are fully
charged. At that point, the FET is fully on, for the smallest
voltage drop across it. Figure 25 below illustrates the typical
inrush current response resulting from a hot insertion for the
following conditions:
turned off by discharging the GATE pin to V . This will
EE
enable the Over-Current latch and the PWRGD/PWRGD
output will transition to the inactive state to indicate power is
no longer good. To clear the latch and initiate a normal power-
up sequence, the user must either power down the system
(below the UVLO voltage), or toggle the UV pin below and
above its threshold (usually with an external transistor). Figure
26 below shows the Over-Current shut down and current
limiting response for a 10Ω short to ground on the output. With
• V = -48V, Rsense = 0.02Ω (2.5A current limit)
EE
• C1 = 150nF, C2 = 3.3nF, R3 = 18kΩ
• I
= 50µA (100µF/3.3nF) = 1.5A
• C = 100uF, R = 150Ω (48V/150Ω = 320mA)
Inrush
L
L
FIGURE 26. CURRENT LIMITING AND TIMEOUT
FIGURE 25. INRUSH CURRENT LIMITING FOR A HOT
INSERTION
a 10Ω short and a -48V supply, the initial fault current is
approximately 4.8A, producing a voltage drop across the
0.02Ω sense resistor of 95mV, roughly two times the Over-
Current threshold of 50mV. This enables the 600µs timer and
the GATE is quickly pulled low to limit the current to 2.5A
(50mV/Rsense). The fault condition persists for the duration of
the time-out period and the GATE is latched off in about
670µs. There is a short filter (3µs nominal) on the comparator,
so current transients shorter than this will be ignored. Longer
transients will initiate the GATE pull down, current limiting, and
the timer. If the fault current goes away before the time-out
period expires the device will exit the current limiting mode
and resume normal operation.
After the contact bounce subsides the UVLO and UV criteria
are quickly met and the GATE begins to ramp up. As the
GATE reaches approximately 4V with respect to the source,
the FET begins to turn on allowing current to charge the load
capacitor. As the drain to source voltage begins to drop, the
feedback network of C2 and R3 hold the GATE constant, in
this case limiting the current to approximately 1.3A. When
the DRAIN voltage completes its ramp down the load current
remains constant at 320mA as the GATE voltage increases
to its final value.
13
ISL6141, ISL6151
In addition to the above current limit and 600µs time-out,
comparator with a nominal reference of 1.255V. A resistor
divider between the V (gnd) and V is typically used to
there is a Hard Fault comparator to respond to short circuits
with an immediate GATE shutdown (typically 10µs) and a
single retry. The trip point of this comparator is set ~4 times
(210mV) higher than the Over-Current threshold of 50mV. If
the Hard Fault comparator trip point is exceeded, a hard pull
down current (350mA) is enabled to quickly pull down the
GATE and momentarily turn off the FET. The fast shutdown
resets the 600µs timer and is followed by a soft start, single
retry event. If the fault is still present after the GATE is slowly
turned on, the current-limit regulator will trip (sense pin
voltage > 50mV), turn on the timer, and limit the current to
50mV/Rsense for 600µs before latching the GATE pin low.
Note: Since the 600µs timer starts when the SENSE pin
exceeds the 50mV threshold, then depending on the speed of
the current transient exceeding 200mV, it’s possible that the
current limit time-out and shutdown can occur before the Hard
Fault comparator trips (and thus no retry). Figure 27 illustrates
the Hard Fault response with a zero ohm short circuit at the
output.
DD
EE
set the trip points on the UV and OV pins. If the voltage on
the UV pin is above its threshold and the voltage on the OV
pin is below its threshold, the supply is within its operating
range and the GATE will be allowed to turn on, or remain on.
If the UV pin voltage drops below its high to low threshold, or
the OV pin voltage increases above its low to high threshold,
the GATE pin will be pulled low, turning off the FET until the
supply is back within tolerance.
The OV and UV inputs are high impedance, so the value of
the external resistor divider is not critical with respect to input
current. Therefore, the next consideration is total current; the
resistors will always draw current, equal to the supply
voltage divided by the total resistance of the divider
(R4+R5+R6) so the values should be chosen high enough to
get an acceptable current. However, to the extent that the
noise on the power supply can be transmitted to the pins, the
resistor values might be chosen to be lower. A filter capacitor
from UV to V or OV to V is a possibility, if certain
EE EE
transients need to be filtered. (Note that even some
transients which will momentarily shut off the GATE might
recover fast enough such that the GATE or the output current
does not even see the interruption).
Finally, take into account whether the resistor values are
readily available, or need to be custom ordered. Tolerances
of 1% are recommended for accuracy. Note that for a typical
48V system (with a 43V to 72V range), the 43V or 72V is
being divided down to 1.255V, a significant scaling factor. For
UV, the ratio is roughly 35 times; every 3mV change on the
UV pin represents roughly 0.1V change of power supply
voltage. Conversely, an error of 3mV (due to the resistors, for
example) results in an error of 0.1V for the supply trip point.
The OV ratio is around 60. So the accuracy of the resistors
comes into play.
The hysteresis of the comparators is also multiplied by the
scale factor of 35 for the UV pin (35 * 135mV = 4.7V of
hysteresis at the power supply) and 60 for the OV pin (60 *
25mV = 1.5V of hysteresis at the power supply).
FIGURE 27. HARD FAULT SHUTDOWN AND RETRY
As in the Over-Current response discussed previously the
supply is set at -48V and the current limit is set at 2.5A. After
the initial gate shutdown (10µs) a soft start is initiated with
the short circuit still present. As the GATE slowly turns on the
current ramps up and exceeds the Over-Current threshold
(50mV) enabling the timer and current limiting. The fault
remains for the duration of the time-out period and the GATE
pin is quickly pulled low and latched off requiring a UVLO or
UV reset to resume normal operation (assuming the fault
has gone away).
With the three resistors, the UV equation is based on the
simple resistor divider:
1.255 = V
* (R5 + R6)/(R4 + R5 + R6) or
= 1.255 (R4 + R5 + R6)/(R5 + R6)
UV
V
UV
Similarly, for OV:
1.255 = V * (R6)/(R4 + R5 + R6) or
OV
= 1.255 (R4 + R5 + R6)/(R6)
V
OV
Note that there are two equations, but 3 unknowns. Because
of the scale factor, R4 has to be much bigger than the other
two; chose its value first, to set the current (for example, 50V /
500kΩ draws 100µA), and then the other two will be in the
10kΩ range. Solve the two equations for two unknowns. Note
that some iteration may be necessary to select values that
Applications: OV and UV
The UV and OV pins can be used to detect Over-Voltage and
Under-Voltage conditions on the input supply and quickly
shut down the external FET. Each pin is tied to an internal
14
ISL6141, ISL6151
meet the requirement, and are also readily available standard
values.
The three resistor divider (R4, R5, R6) is the recommended
approach for most cases. But if acceptable values can’t be
found, then consider 2 separate resistor dividers (one for
each pin, both from V
to V ). This also allows the user to
DD
EE
adjust or trim either trip point independently. Some
applications employ a short pin ground on the connector tied
to R4 to ensure the hot plug device is fully powered up
before the UV and OV pins (tied to the short pin ground) are
biased. This ensures proper control of the GATE is
maintained during power up. This is not a requirement for the
ISL6141/51 however the circuit will perform properly if a
short pin scheme is implemented (reference Figure 34).
Supply ramping
As previously mentioned the UV and OV pins can be used to
detect under and Over-Voltage conditions on the input
supply. Figures 28 and 29 illustrate the GATE shutdown
response and the UV/OV hysteresis as a typical power
supply is ramped from 0 to 80V, and then from 80V to 0V.
FIGURE 29. SUPPLY RAMP-DOWN
Applications: PWRGD/PWRGD
The PWRGD/PWRGD outputs are typically used to directly
enable a power module, such as a DC/DC converter. The
PWRGD (ISL6141) is used for modules with active low
enable (L version), and PWRGD (ISL6151) for those with
active high enable (H version). The modules usually have a
pull-up device built-in, as well as an internal clamp. If not, an
external pull-up resistor may be needed. If the pin is not
used, it can be left open.
For both versions at initial start-up, when the DRAIN to V
EE
voltage differential is less than 1.3V and the GATE voltage is
within 2.5V (V ) of its normal operating voltage (13.6V),
GH
power is considered good and the PWRGD/PWRGD pins
will go active. At this point the output is latched and the
DRAIN is no longer criticized. The latch is reset by any of the
signals that shut off the GATE (Over-Voltage, Under-Voltage;
Under-Voltage-Lock-Out; Over-Current Time-Out or
powering down). In this case the PWRGD/PWRGD output
will go inactive, indicating power is no longer good.
ISL6141 (L version; Figure 30): Under normal conditions
FIGURE 28. SUPPLY RAMP-UP
(DRAIN voltage - V < V , and ∆V
- V
< V )
EE PG GATE
GATE
GH
the Q2 DMOS will turn on, pulling PWRGD low, enabling the
module.
As the supply ramps up, the UV threshold is reached at
43.6V and the FET begins to turn on. Within 40ms the GATE
is fully on and the device is operating normally. As the supply
continues to ramp up the Over-Voltage threshold is
exceeded at approximately 70.5V and the GATE is quickly
shut down as expected. In figure 29 the GATE voltage
begins in the off state as the supply voltage is above the OV
set point. As the supply voltage decreases the GATE turns
on at about 69V (roughly a 1.5 volt hysteresis). Some 800ms
later (a characteristic of the supply used) the UV high to low
threshold is met at approximately 38.5 volts (about 5.0V of
hysteresis) and the GATE is shut off.
VDD
VIN+ VOUT+
∆ V
(SECTION OF) ISL6141
GATE
PWRGD
(L VERSION)
V
GH
ON/OFF
-
ACTIVE LOW
ENABLE
Q2
+
CL
GATE
+
LOGIC
+
LATCH
V
MODULE
PG
+
-
+
-
V
EE
DRAIN
VOUT-
VIN-
V
EE
FIGURE 30. ACTIVE LOW ENABLE MODULE
15
ISL6141, ISL6151
When any of the 4 conditions occur that turn off the GATE
(OV, UV, UVLO, Over-Current Time-Out) the PWRGD latch
is reset and the Q2 DMOS device will shut off (high
pin. This should be able to pull low against the module pull-
up current, and disable the module.
VDD
impedance). The pin will quickly be pulled high by the
external module (or an optional pull-up resistor or equivalent)
which in turn will disable it. If a pull-up resistor is used, it can
be connected to any supply voltage that doesn’t exceed the
IC pin maximum ratings on the high end, but is high enough
to give acceptable logic levels to whatever signal it is driving.
An external clamp may be used to limit the voltage range.
VIN+ VOUT+
∆
V
PWRGD
(SECTION OF) ISL6151
(H VERSION)
GATE
V
GH
RPG
-
ON/OFF
6.2K
GATE
+
+
ACTIVE HIGH
ENABLE
LOGIC
CL
Q2
+
V
PG
LATCH
MODULE
+
-
Q3
V
+
-
V
DD
V
EE
EE
DRAIN
VIN- VOUT-
∆ V
(SECTION OF) ISL6141
GATE
PWRGD
R12
(L VERSION)
FIGURE 33. ACTIVE HIGH ENABLE MODULE
V
GH
PWRGD
-
GATE
+
Q2
OPTO
LOGIC
+
LATCH
Applications: GATE pin
V
PG
To help protect the external FET, the output of the GATE pin
is internally clamped; up to an 80V supply and will not be any
higher than 15V. Under normal operation when the supply
voltage is above 20V, the GATE voltage will be regulated to a
+
-
+
-
V
EE
V
EE
DRAIN
nominal 13.6V above V
.
FIGURE 31. ACTIVE LOW ENABLE OPTO-ISOLATOR
EE
Applications: “Brick” Regulators
The PWRGD can also drive an opto-coupler (such as a
4N25), as shown in Figure 31 or LED (Figure 32). In both
cases, they are on (active) when power is good. Resistors
R12 or R13 are chosen, based on the supply voltage, and
the amount of current needed by the loads.
One of the typical loads used are DC/DC regulators, some
commonly known as “brick” regulators, (partly due to their
shape, and because it can be considered a “building block”
of a system). For a given input voltage range, there are
usually whole families of different output voltages and
current ranges. There are also various standardized sizes
and pinouts, starting with the original “full” brick, and since
getting smaller (half-bricks and quarter-bricks are now
common).
V
DD
∆ V
(SECTION OF) ISL6141
GATE
PWRGD
(L VERSION)
R13
V
GH
-
GATE
+
Q2
LOGIC
+
LATCH
LED (GREEN)
Other common features may include: all components (except
some filter capacitors) are self-contained in a molded plastic
package; external pins for connections; and often an
ENABLE input pin to turn it on or off. A hot plug IC, such as
the ISL6141 is often used to gate power to a brick, as well as
turn it on.
V
PG
+
-
+
-
V
EE
V
EE
DRAIN
FIGURE 32. ACTIVE LOW ENABLE WITH LED
Many bricks have both logic polarities available (Enable Hi or
Lo input); select the ISL6141 (L version) and ISL6151 (H
version) to match. There is little difference between them,
although the L version output is usually simpler to interface.
ISL6151 (H version; Figure 33): Under normal conditions
(DRAIN voltage - V < V , and ∆V
- V
< V ),
EE PG GATE
GATE
GH
the Q3 DMOS will be on, shorting the bottom of the internal
resistor to V , and turning Q2 off. If the pull-up current from
EE
the external module is high enough, the voltage drop across
the 6.2kΩ resistor will look like a logic high (relative to
DRAIN). Note that the module is only referenced to DRAIN,
The Enable input often has a pull-up resistor or current
source, or equivalent built in; care must be taken in the
ISL6151 (H version) output that the given current will create
a high enough input voltage (remember that current through
the RPG 6.2kΩ resistor generates the high voltage level; see
Figure 33).
not V (but under normal conditions, the FET is on, and the
EE
DRAIN and V are almost the same voltage).
EE
When any of the 4 conditions occur that turn off the GATE,
the Q3 DMOS turns off, and the resistor and Q2 clamp the
PWRGD pin to one diode drop (~0.7V) above the DRAIN
The input capacitance of the brick is chosen to match its
system requirements, such as filtering noise, and
maintaining regulation under varying loads. Note that this
input capacitance appears as the load capacitance of the
ISL6141/51.
16
ISL6141, ISL6151
The brick’s output capacitance is also determined by the
When placed from V
to V on the board, it will clamp the
EE
DD
system, including load regulation considerations. However, it
can affect the ISL6141/51, depending upon how it is
enabled. For example, if the PWRGD signal is not used to
enable the brick, the following could occur. Sometime during
the inrush current time, as the main power supply starts
charging the brick input capacitors, the brick itself will start
working, and start charging its output capacitors and load;
that current has to be added to the inrush current. In some
cases, the sum could exceed the Over-Current shutdown,
which would shut down the whole system! Therefore,
whenever practical, it is advantageous to use the PWRGD
output to keep the brick off at least until the input caps are
charged up, and then start-up the brick to charge its output
caps.
voltage.
If transients on the input power supply occur when the
supply is near either the OV or UV trip points, the GATE
could turn on or off momentarily. One possible solution is to
add a filter cap C4 to the V
R10. A large value of R10 is better for the filtering, but be
pin, through isolation resistor
DD
aware of the voltage drop across it. For example, a 1kΩ
resistor, with 2.4mA of I
would have 2.4V across it and
DD
dissipate 2.4mW. Since the UV and OV comparators are
referenced with respect to the V supply, they should not
be affected. But the GATE clamp voltage could be offset by
the voltage across the extra resistor.
EE
The switch SW1 is shown as a simple push button. It can be
replaced by an active switch, such as an NPN or NFET; the
principle is the same; pull the UV node below its trip point,
and then release it (toggle low). To connect an NFET, for
example, the DRAIN goes to UV; the source to V , and the
GATE is the input; if it goes high (relative to V ), it turns the
EE
Typical brick regulators include models such as Lucent
JW050A1-E or Vicor VI-J30-CY. These are nominal -48V
input, and 5V outputs, with some isolation between the input
and output.
EE
NFET on, and UV is pulled low. Just make sure the NFET
resistance is low compared to the resistor divider, so that it
has no problem pulling down against it.
Applications: Optional Components
In addition to the typical application, and the variations
already mentioned, there are a few other possible
components that might be used in specific cases. See Figure
34 for some possibilities.
R8 is a pull-up resistor for PWRGD, if there is no other
component acting as a pull-up device. The value of R8 is
determined by how much current is needed when the pin is
If the input power supply exceeds the 100V absolute
maximum rating, even for a short transient, that could cause
permanent damage to the IC, as well as other components
on the board. If this cannot be guaranteed, a voltage
suppressor (such as the SMAT70A, D1) is recommended.
pulled low (also affected by the V
voltage); and it should
DD
be pulled low enough for a good logic low level. An LED can
also be placed in series with R8, if desired. In that case, the
criteria is the LED brightness versus current.
GND
GND
R10*
R4
GND
R8*
(SHORT PIN)
V
DD
UV
OV
ISL6141 (L)
G
R5
R6
PWRGD
DRAIN
SW1*
V
SENSE
GATE
EE
NFET*
(INSTEAD
OF SW1)
D1*
CL*
C4*
R3
C2
C1
R2
-V IN
R1
Q1
-V OUT
FIGURE 34. ISL6141/51 OPTIONAL COMPONENTS (SHOWN WITH *)
17
ISL6141, ISL6151
Note that with the placement shown, most of the signal lines
are short, and there should not be minimal interaction
between them.
Applications: Layout Considerations
For the minimum application, there are only 6 resistors, 2
capacitors, one IC and one FET. A sample layout is shown in
Figure 35. It assumes the IC is 8-SOIC; the FET is in a
D2PAK (or similar SMD-220 package).
Although decoupling capacitors across the IC supply pins
are often recommended in general, this application may not
need one, nor even tolerate one. For one thing, a decoupling
cap would add to (or be swamped out by) any other input
capacitance; it also needs to be charged up when power is
applied. But more importantly, there are no high speed (or
any) input signals to the IC that need to be conditioned. If still
desired, consider the isolation resistor R10, as shown in
Figure 34.
Although GND planes are common with multi-level PCBs, for
a -48V system, the -48V rails (both input and output) act
more like a GND than the top 0V rail (mainly because the IC
signals are mostly referenced to the lower rail). So if
separate planes for each voltage are not an option, consider
prioritizing the bottom rails first.
GND
GND
C2
R3
R2
C1
VDD 8
D 7
1 PG
2 OV
3 UV
4 VEE
R6
G
DRAIN
U1
FET
G 6
R5
R4
S 5
S
R1
-48V OUT
-48V IN
GND
GND
R4
V
DD
UV
OV
PWRGD
R5
R6
ISL6141
SENSE GATE
C1
V
DRAIN
EE
(LOAD)
R3
C2
CL
R2
RL
-48V IN
R1
Q1
-48V OUT
FIGURE 35. ISL6141/51 SAMPLE LAYOUT (NOT TO SCALE)
NOTES:
1. Layout scale is approximate; routing lines are just for illustration
purposes; they do not necessarily conform to normal PCB
design rules. High current buses are wider, shown with parallel
lines.
BOM (Bill Of Materials)
R1 = 0.02Ω (5%)
R2 = 10Ω (5%)
R3 = 18kΩ (5%)
2. Approximate size of the above layout is 1.6 x 0.6 inches; almost
half of the area is just the FET (D2PAK or similar SMD-220
package).
R4 = 549kΩ (1%)
R5 = 6.49kΩ (1%)
R6 = 10kΩ (1%)
3. R1 sense resistor is size 2512; all other R’s and C’s shown are
0805; they can all potentially use smaller footprints, if desired.
C1 = 150nF (25V)
C2 = 3.3nF (100V)
Q1 = IRF530 (100V, 17A, 0.11Ω)
4. The RL and CL are not shown on the layout.
5. R4 uses a via to connect to GND on the bottom of the board; all
other routing can be on top level. (It’s even possible to eliminate
the via, for an all top-level route).
6. PWRGD signal is not used here.
18
ISL6141, ISL6151
Small Outline Plastic Packages (SOIC)
M8.15 (JEDEC MS-012-AA ISSUE C)
N
8 LEAD NARROW BODY SMALL OUTLINE PLASTIC
PACKAGE
INDEX
AREA
0.25(0.010)
M
B M
H
E
INCHES
MILLIMETERS
-B-
SYMBOL
MIN
MAX
MIN
1.35
0.10
0.33
0.19
4.80
3.80
MAX
1.75
0.25
0.51
0.25
5.00
4.00
NOTES
A
A1
B
C
D
E
e
0.0532
0.0040
0.013
0.0688
0.0098
0.020
-
1
2
3
L
-
9
SEATING PLANE
A
0.0075
0.1890
0.1497
0.0098
0.1968
0.1574
-
-A-
o
h x 45
D
3
4
-C-
α
µ
0.050 BSC
1.27 BSC
-
e
A1
H
h
0.2284
0.0099
0.016
0.2440
0.0196
0.050
5.80
0.25
0.40
6.20
0.50
1.27
-
C
B
0.10(0.004)
5
0.25(0.010) M
C A M B S
L
6
N
α
8
8
7
NOTES:
o
o
o
o
0
8
0
8
-
1. Symbols are defined in the “MO Series Symbol List” in Section 2.2 of
Publication Number 95.
Rev. 0 12/93
2. Dimensioning and tolerancing per ANSI Y14.5M-1982.
3. Dimension “D” does not include mold flash, protrusions or gate burrs.
Mold flash, protrusion and gate burrs shall not exceed 0.15mm (0.006
inch) per side.
4. Dimension “E” does not include interlead flash or protrusions. Inter-
lead flash and protrusions shall not exceed 0.25mm (0.010 inch) per
side.
5. The chamfer on the body is optional. If it is not present, a visual index
feature must be located within the crosshatched area.
6. “L” is the length of terminal for soldering to a substrate.
7. “N” is the number of terminal positions.
8. Terminal numbers are shown for reference only.
9. The lead width “B”, as measured 0.36mm (0.014 inch) or greater
above the seating plane, shall not exceed a maximum value of
0.61mm (0.024 inch).
10. Controlling dimension: MILLIMETER. Converted inch dimensions
are not necessarily exact.
All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems.
Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without
notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and
reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result
from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see www.intersil.com
19
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